What is VTP and what are the different VTP modes?

VTP (VLAN Trunking Protocol) is a Cisco proprietary protocol used to exchange VLAN information by Cisco switches. With VTP, we can synchronize VLAN information (like VLAN ID or VLAN name) inside the same VTP domain.

A network switch, which is participating in VTP domain, Can be configured in three different modes. 

� Server Mode

� Client Mode

� Transparent Mode

VTP Server Mode

The default VTP mode for all cisco catalyst switches is server mode. In the VTP domain at least one server switch is required to propagate VLAN information like VLAN name and ID. We can create, add, modify or delete VLAN information of a VTP domain by the Switch which is in VTP Server mode. Any changes made in a switch which is in server mode are advertised to the entire VTP domain. 

VTP Client Mode

VTP client mode switches listen to VTP advertisements coming from other switches and modify their VLAN configurations accordingly and they also share the VTP advertisements with other switches in the VTP domain. A network switch in VTP client mode requires a server switch to modify or change their VLAN information. We can not create, add, modify or delete VLAN information in a switch which is in VTP client mode.

VTP Transparent Mode

VTP transparent mode switches do not change or modify their VLAN configuration according to the VTP Server switch, but they can receive and forward the VTP advertisements coming from VTP server switch to other switches through the configured trunk links.